Seventy four consecutive patients diagnosed as normal pressure hydrocephalus (NPH) and operated with a ventriculo-peritoneal shunt were followed prospectively for an average of 2.1 years. The mean age was 64 years. The effect of the operation was estimated by calculating 6 indices expression social functioning, neurological signs, gait ability, continence, psychometric performance and psychiatric condition. Ninety-six % had mental symptoms, 95% gait disturbances and 75% incontinence. Improvement was observed in 78% after shunt surgery, while 22% deteriorated. Psychiatric improvement was seen in 80% and 76% improved in gait ability. Improvement was highest in the group caused by subarachnoid hemorrhage (98%) while 73% with idiopathic NPH improved. Old age was not correlated to poorer response, while long-standing pre-operative symptoms yielded worse results. No single symptom or sign could predict a positive outcome of the operation. Eleven % of the patients could leave long-term care institutions and there was a 36% reduction of aid in daily living. Complications to shunt surgery were observed in 50% of the patients and shunt related mortality was 1%. Shunt malfunction was the most frequent complication (31%) followed by infection (19%). Epilepsy developed in 9% after surgery. All shunt complication except one appeared within the first year after surgery.

Relative regional cerebral blood flow (rrCBF) was measured by single-photon emission tomography (SPET), using technetium-99m-d,l-hexamethylpropylene amine oxime (HMPAO) as flow tracer, in 23 patients with normal pressure hydrocephalus (NPH). 1000 MBq 99mTc-HMPAO was given intravenously and the rrCBF calculated as regional/cerebellar count level ratios. The patients were examined before and 3-12 months after ventriculoperitoneal shunt surgery. rrCBF was also determined in ten healthy aged matched volunteers who served as controls. The NPH patients had decreased rrCBF in the hippocampal regions and in the frontal and parietal white matter as compared to the controls. The frontal/parietal rrCBF ratio correlated with both psychiatric disability and the preoperative degree of incontinence. Decreased flow in frontal white matter, frontoparietal and hippocampal grey matter and a low frontalparietal grey matter flow ratio preoperatively correlated with improvement in both Mini Mental State score and psychiatric disability after shunt surgery. After shunt surgery the rrCBF increased in the mesencephalon, frontal grey and white matter, parietal white matter and hippocampus. The flow increase in hippocampal regions and frontal white matter correlated with improvement in psychiatric symptomatology. The results of this study regarding the frontal and hippocampal rrCBF patterns, and the clinical correlation, support the hypothesis that CBF changes in these regions are of pathophysiological and prognostic importance in NPH.

23 patients with normal pressure hydrocephalus (NPH) underwent psychiatric examinations prior to and 80 days to 10 months after a ventriculo-peritoneal shunt operation. A global evaluation of the effect of the operation on the patients' mental symptoms indicated appreciable improvement in 10 cases and slight improvement in a further 4. 8 patients were assessed as unchanged, and one as mentally deteriorated. The psychiatric analyses was based on a new diagnostic system created by two of the authors (G.L., H.M.). The patients manifested varying, often complex psychiatric symptom constellations with symptomatological components from two or more organic mental disorders. Before the operation a mild o r a moderately severe somnolence-sopor-coma disorder (SSCD) was diagnosed in 10 cases. After the operation all these patients became free from symptoms of SSCD. This was the most unequivocal change in connection with the operation, and the elimination of all symptoms of SSCD was the single factor which most effectively contributed to the total therapeutical result in these patients. All 23 cases were considered to have symptoms of a more or less severe astheno-emotional disorder (AEI)) preoperatively. The degree of severity of this disorder could not be determined with satisfactory certainty in some of the patients with complex symptoms. Amongst the 17 cases where the preoperative symptomatology allowed for a reasonably precise calculation of the degree of severity of AED, 6 were assessed as markedly improved after the operation and 10 as largely unchanged. In one patient, symptoms of the AED increased when the postoperative course was complicated by a subdural haematoma. Symptoms of an emotional-motivational blunting disorder (EMI)) were diagnosed in 5 cases before the operation. After the operation 3 of these patients were symptom free in this respect while 2 were unchanged. Slight o r moderately severe symptoms of Korsakoffs amnestic disorder (KAD) were before the operation found in 7 cases: at the postoperative examination 6 of these cases were improved, of which 4 were free from such symptoms; one was unchanged. According to our experience, confident prognoses concerning the effect of the shunt operation on symptoms of SSCD can be made preoperatively, while, for a particular patient, the therapeutic effect on AED, EM11 and KAD is often difficult, or sometimes impossible, to foresee. This article contains three case reports which represent different forms and courses of the mental symptom patterns.,.

Thirteen patients with normal pressure hydrocephalus were operated upon with an externally maneuverable shunt system (Sophy SU8) in order to investigate its influence on clinical outcome, intracranial pressure and cranial CT parameters. The opening pressure was set at high at surgery and lowered stepwise at intervals of three months to medium and low. The clinical condition, intracranial pressure and cranial CT parameters were examined at the end of the 3 months interval on each pressure level. The patients improved within the first 3 months inspite of an unchanged mean intracranial pressure and remained in a stable clinical condition during the rest of the study period. The intracranial pressure was significantly reduced at 9 months. The ventricular index, Evans index, temporal horn and third ventricle width were reduced 3 months post-operatively and did not change significantly during the rest of the study. The pre-operative third ventricle width was correlated to high psychometric test results after shunt surgery. Reduction in ventricular index, Evans index and third ventricle width after surgery correlated to improvement in psychometric scoring. The clinical improvement after shunt surgery for normal pressure hydrocephalus is seen within 3 months and is independent of the adjusted valve pressure.